With the availability of more advanced and precise diagnostic instruments, machines, and systems, medical science can more accurately pinpoint malfunctions and diseases of the body and often apply corrective measures. However, quite often the disease is detected at too late a stage to fully correct the problem, whereas if the developing malfunction had been found earlier, corrective measures may have resulted in a complete cure or at least arresting or neutralizing of the problem.
The reasons for late detection often result from economic inability, neglect, or the unavailability of doctors and needed medical facilities. Although medical authorities recommend periodic medical examinations, the individuals involved often cannot afford the costs of such examinations and testing, and medical insurance policies often do not include the costs of such diagnostic exams and tests unless accompanied by a known specific illness or disorder. Additionally, in an increasingly mobile society, individuals frequently relocate from place to place, and change doctors and other medical services more frequently than in the past. Therefore the doctors often do not have the benefit of long term medical histories of their patients but instead must rely upon limited medical information known by the patients themselves, together with the result of current physical examinations and tests, without the benefit of earlier, more complete medical records pertaining to that individual.
As a result, medical examinations and diagnosis of an individual is often based entirely upon such current information without the benefit of past medical history. Quite often these current measurements and tests only shown results within the so-called normal ranges, that are typical or average of data taken from other individuals, and therefore do not alert the medical examiner to a problem that is in progress but that has not progressed to outside the range of the "average" reading or measurement. On the other hand, if the physician had available a detailed series of past medical tests and findings for comparison, the "trends" or changes in the measured conditions over a long term interval would often alert the diagnostician of a problem in process, or raise suspicions about the onset of a possibly adverse condition that should be more thoroughly checked by further testing. For example, current blood testing might indicate a patient's blood sugar level to be within a so-called normal range, yet comparison of that test with a series of earlier tests of the same individual might reveal a progressive increase in the blood sugar level over the past few years, or other long term interval. This adverse "trend" would then indicate the need for further testing, by such means as a glucose tolerance test, or other, which is not usually given during a routine medical examination. If such further testing confirms the suspicion of onset of a diabetic problem, the physician might then seek to stabilize the patient by change in diet coupled with medication, exercise, and other procedures recommended.